This invention relates to a chain stopper for a round bar iron chain, particularly a ship's anchor chain, including two guideways for the horizontally oriented links of the chain, these two guideways being arranged parallel with respect to the longitudinal direction of the chain and forming therebetween a groove for guiding the vertically oriented links of the chain, and further including at least one clamping lever which can be swung about a horizontal pin above the chain and which includes apparatus for locking the chain under tension.
So-called "chain stoppers" which are located between the hawse pipe and the capstan are used in order to secure ships lying at anchor and, at the same time, in order to relieve the capstan of the pull of the anchor chain with the anchor hanging thereon. These chain stoppers have to be arranged in such a way that they can absorb stresses up to the breaking load (or strain) of the anchor chain, without damage to the chain links being able to occur before the breaking load is reached.
In the case of the so-called "wedge stoppers" ("dog type") used up to now, the chain is led via a guideway and the vertically oriented chain link is locked by a steel rod with an approximately rectangular cross section, which lies at right angles to the upper open side of the guide. In so doing, the vertically oriented chain link is being held only unilaterally, i.e. only in single shear. As shown in practice, this single-shear locking of the chain link is not sufficient in order to absorb stresses up to the chain breaking load.
A chain stopper for a round bar iron chain is also known, in which two clamping jaws are provided, which are arranged symmetrically with respect to the longitudinal direction of the chain, are movable in the horizontal plane and serve in order to lock the chain under tension. These clamping jaws can be swung about vertical pins arranged on both sides of the chain guide. These clamping jaws, moreover, are designed in such a way that, seen in the direction of the anchor pull, they engage on the other side of the swivel pins of their lever arms and position themselves in a locking orientation in front of the chain link to be held. In order to actuate the clamping jaws, a threaded spindle is provided which engages longer swivel arms which are connected to the clamping jaw levers, so that the opening and the closing of the clamping jaws requires a longer length of time, depending on the actuation of the threaded spindle.
However, a chain stopper of this type is extremely bulky and, for this reason, cannot readily be installed subsequent to the original building and outfitting of a ship. Furthermore, the stresses occurring at the clamping jaws have to be absorbed by the threaded spindle via the clamping jaws and the swivel levers connected thereto.
The purpose of the present invention is to provide a chain stopper of the type mentioned hereinbefore in as space-saving a manner of construction as possible, in such a way that the stresses applied to the shaped parts of the clamping levers do not have to be absorbed by movable parts of the chain stopper, but will be intercepted by fixed abutment parts.
According to the invention, this object finds its solution in the fact that two pawl sections are arranged side by side in parallel and between each other allow a vertical slit to remain free for the passage of the vertical links of the chain, and in the fact that the pawl sections are of such a length that in the stopping position they engage, in a locking manner, in responses on the guideways for the horizontal links of the chain. In so doing, as seen in the direction of pull of the anchor, the shaped parts of the clamping levers encircle the horizontal link of the chain in such a form-locking manner that due to the resulting double shear connection, the horizontal link of the chain is in the position of absorbing stresses up to the chain breaking load, without damage to the chain or to the chain stopper. Such a chain stopper thereby guarantees not only a secure locking of the anchor chain, but also can be designed in such a compact manner that with its base plate it can be mounted subsequently on already existing fastening devices.
In a preferred form of embodiment of the invention it is provided that the pawl sections are arranged on two clamping levers which can be swung about a common horizontal pin in parallel to each other.
In order that the horizontal chain link held by the pawl sections finds a secure support on the shaped pieces, according to a further characteristic of the invention, it is provided for that the pawl sections have recesses adapted to the shape of the horizontal links of the chain and these recesses engage the rounded portions of the chain link concerned, on both sides of the subsequent vertically oriented link of the chain.
According to a further characteristic of the invention, each of the two recesses in the guideways is designed with a vertical abutment surface for the associated pawl section with this vertical abutment surface lying in the direction of pull of the anchor. The clamping levers are constructed as two-armed levers and carry counterweights at their extremity, so that the clamping levers can also be easily swung out of their locking position by hand.